Papers by Keyword: Titanium Hydride

Abstract: The results of experimental studies of the protective properties of titanium hydride with respect to neutron and gamma radiation in order to determine the optimal conditions for their use in the composition of the structural radiation protection of the nuclear reactor are presented. The weakening of the basic functionals in the thickness of protection, including the density of fast, intermediate and thermal neutrons, and the dose rate of gamma radiation is established. The functions of weakening the density of neutron flow and the dose rate of gamma radiation are measured in the conditions of "barrier" geometry. Determination of the protective properties of the structure was carried out when the modified titanium hydride fraction was placed in aluminum containers with a filling coefficient of a volume of container 0.63. The relaxation lengths for all neutron groups are close and on average are 9.8 cm. The functions of weakening the dose rate of gamma radiation of point sources Cs-137 and Co-60 are exponential. The weakening of radiation occurs with a constant relaxation length. For energy 0.661 MeV, the relaxation length is 7.1 cm, for energy 1.25 MeV, the relaxation length is equal to 10.1 cm. On the basis of the experimental studies, the high efficiency of the modified fraction of titanium hydride was confirmed during its use in protecting nuclear power plants.

Abstract: This paper presents an analysis of known radiation protection materials. The prospects of using materials based on titanium hydride are shown. The possibility of obtaining finely ground titanium hydride with a high content of atomic hydrogen in its structure has been established. The features of the physicochemical interaction of dispersed titanium hydride and heavy flint, after hydrolysis in the alkaline environment of the organosilicon modifier – tetraethoxysilane, are revealed. The possibility of obtaining a thermostable low-activated composite material based on dispersed titanium hydride for complex protection against neutron and gamma radiation has been established. The structure of the obtained composite was investigated.

Abstract: Hydrogen storage is one of the most important industrial applications of titanium hydride (TiH₂). A critical issue is the hydrogen release rate that strongly depends on the surface structure of TiH₂ particles. This work reports the results of an experimental campaign carried out on TiH₂ powders submitted to heat treatments in air at different temperatures and treatment times. After each heat treatment the TiH₂ powders were examined by X-ray diffraction (XRD) and the results evidenced that the surface layer consists of TiO₂ and Ti₂O. Titanium oxide formation has been monitored by XRD at high temperature. Hydrogen release during heating of oxidized powders was investigated through temperature programmed desorption (TPD). Residual hydrogen in TiH₂ depends on the specific treatment: higher temperature and soaking time of the treatment, lower its content.

Abstract: This paper describes the influence of two-steps sintering regime temperatures concerning the final properties of titanium hydride based alloy obtaining by Two-Steps Sintering (TTS) route, which is a method that is part of the Powder Metallurgy (PM) technology. The initial titanium hydride powder has been mixed with some metallic powders as: Alumix, Mn, Zr, Sn and graphite was added in different proportions for improving the final mechanical properties. The Two-Steps Sintering (TTS) route have been applied for obtaining a low-cost Ti- alloy. The effect of the sintering regime temperatures on the height and diameter shrinkages and density for these alloys based on titanium hydride powder was studied

Abstract: This paper highlights the influence of titanium hydride particle on the rheological behaviour of nickel-titanium feedstock used in the metal injection process. The ratio of 50at% nickel and 50at% titanium hydride with 2 different powder loadings (65.5vol% and 67.5vol%) were investigated. A Rosand RH2000 capillary rheometer was used to determine the flow behaviour of feedstocks. The feedstocks were characterized at different temperature ranging from 150°C and 170°C and shear rate ranging from 50/s and 4442.63/s. The results showed on pseudo-elastic behaviour flow of NiTi feedstock which is suitable for injection moulding process.

Abstract: The present work investigates the effect of heat treatments in air on the surface and structure of titanium hydride (TiH₂) and hydrogen desorption. TiH₂ has been heated in air at 440 and 540 °C for increasing time up to 180 min. to obtain the samples representative of 12 different oxidation conditions. The samples have been then examined by Temperature Programmed Desorption (TPD), X-Ray Diffraction (XRD) and Photoelectron Spectroscopy (XPS). Experimental results are presented and discussed.

Abstract: Titanium has excellent mechanical properties, low density, high chemical stability, good heat transfer properties and a good corrosion resistance. In recent years, a new process technology is emerging by which titanium and titanium alloys can be made by sintering titanium hydride (TiH₂) and its mixture with alloying elements. The feasibility of this manufacturing approach has been fully demonstrated from powder to sintering and from microstructure to mechanical properties. This paper describes a study concerning Powder Metallurgy (PM) technology processing of Ti by conventional PM and non-conventional PM method such as Spark Plasma Sintering (SPS) route. The influence of the technological parameters on the micro-hardness and SEM microstructures during bulk titanium materials processing has been studied. The STATISTICA program has been used to monitor the influence of the technological parameters on the micro-hardness of bulk titanium processed products. The tribological behaviour of the bulk titanium materials on the basis of the coefficient of friction and wear rate is presented, too.

Abstract: Two basic methods can be used to fabricate aluminum foam. One is powder metallurgy route which can provide the near net shape casting containing aluminum foam core, and the other is melt foaming route which can prepare large scale aluminum foam plate directly. To combine the advantages of above two methods, the precursor was obtained through melt foaming route and then baked in a furnace like that of powder metallurgy method in this investigation. The test results indicated that the SiC and TiH₂ particles after treatment in air could be dispersed in Al-Si matrix alloy melt and the precursors were obtained. The porosity and their pore diameter of the precursors decreased along with the temperature reducing as well as the magnesium or SiC particles adding. The density of Al-Si alloy foam decreased with the elevation of baking temperature and extension of heating time before collapse of foam block occurred. The foaming process parameters were seriously affected by the aluminum alloy composition.

Abstract: Titanium-based composites with bioactive phases were produced with TiH₂ and 10% in volume of calcium phosphate. The mixtures were prepared either by conventional powder metallurgy processing or by ultrasound, dried in a rotary evaporator, pressed at 600 MPa and vacuum-sintered at 1200 °C for 2 hours. Crystal phases of the as-fabricated composites are found to be α-Ti, CaTiO₃ and Ti_xP_y phase (s). The Ti_xP_y and CaTiO₃ phases resulted from the reaction between titanium and tricalcium phosphate at about 1130 °C. Calcium phosphate was better dispersed by ultrasound leading to a higher compressive strength of the composite and a more uniform Ca-P deposition in simulated body fluid solution.

Abstract: This work investigates the dehydrogenation of TiH₂ powder during isothermal heating at 600°C using the static x-ray scans of high temperature x-ray diffraction (XRD). As-received TiH₂ powder with a particle size of 5 μm and purity of 99.1% was used for this measurement. With increasing temperature, phase transformations occurred because of dehydrogenation and it happened very fast. It was found that during the phase transformation of TiH₂ to titanium, some transitional phases observed and occurred. This finding confirmed the in-situ determination of TiH₂ powder dehydrogenation by using Rietveld Refinement Method from our previous research. This study is useful for the fabrication of titanium-based composites and titanium alloys from TiH₂ powder because the different phases in TiH₂ will affect the final mechanical properties in titanium.